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Mammoth Springs: A Successful Brownfield Redevelopment


Overlooking a former limestone quarry, the Mammoth Springs Development project site had been a canning factory for decades and sat vacant for 20 years, requiring careful coordination before redeveloping it into a mixed-use commercial property in downtown Sussex, Wisconsin. 

The County owned a 60-foot strip through the center of the site, which had not been open as a trail for over 33 years. Contamination, bedrock, floodplain, and the relocating and opening of the County-owned trail through the site were just a few of the challenges facing the project team.      


SEH coordinated with Sawall Development, the Village of Sussex, Waukesha County, and the Wisconsin Department of Transportation (WisDOT) to reinvigorate the downtown area and attract more residents by redeveloping this 10-acre brownfield site. To ensure the project would ultimately be realized, it took several years to develop a design that balanced the needs of all parties while safeguarding the cost of development.  

Community engagement was crucial in bringing the vision to life and creating a master plan that met the community and developer's needs. The developer recognized the beauty of the quarry and designed it to be the center of the neighborhood, creating a sense of vitality in the area.  

During the mid-planning stage of the project, the national economy took a hit; so the team collaborated with the Village, Waukesha County, and community groups to temporarily open the Bugline Trail through the site. Temporarily opening the trail in the County's 60' wide ownership strip until the development moved forward was tremendously beneficial. From there, the box culvert was removed and reconstructed, and the Bugline Trail was realigned along Spring Creek, completing a 17-mile segment connecting the neighborhood to retail, work, and recreational options in several communities. 

A key element in the project's success involved revising the WisDOT reconstruction of State Trunk Highway (STH) 74 to realign the floodplain with the existing creek, thereby increasing the property's redevelopment potential. Based on bedrock limitations, the team also realigned architectural site plans to reduce costs and ensure that stormwater measures remained within reasonable limits.     

The Mammoth Springs Redevelopment project resulted in 153 apartments and 32,000 sq. ft. of commercial space in two bi-level buildings, forming the gateway to Downtown Sussex and contributing over $20 million in additional tax base for the Village. Collage of project images

Mammoth Springs Development

Sussex, Wisconsin

Sawall Development


  • 153 new apartments and 32,000 sq. ft. of commercial space in two bi-level buildings
  • The Bugline Trail’s opening through the site links the neighborhood to various shops, workplaces, and recreational activities across several communities via a 17-mile stretch.


  • Civil engineering
  • Surveying
  • Site design
  • Water resource engineering